1. Field of the Invention
The present invention relates to a paper discharge apparatus attached to a printer for use in discharging a continuous recorded paper such as a printed receipt, ticket, etc.
2. Description of the Prior Art
In a conventional printer adapted for use in an issuing apparatus for issuing a receipt, ticket, etc., a continuous paper is printed and discharged, then cut off upon completion of printing.
FIG. 21A shows an outer appearance of the conventional printer. A paper discharge port 306 is provided at a front surface panel portion 304 of an outer casing 302. A continuous paper 308 is discharged from the paper discharge port 306 depending on the printing operation while it is printed. A recipient can receive the discharged paper 308 while picking up it with fingers.
FIG. 21B shows an internal structure of the conventional printer. There is formed a paper feed passage 310 which extends from the inside of the outer casing 302 to the paper discharge port 306. A paper feed mechanism 312, a print mechanism 314 and a cutter mechanism 316 are respectively provided on the paper feed passage 310. The paper feed mechanism 312 is a means for feeding the paper 308 in synchronization with printing. The paper feed mechanism 312 is provided with a pair of driving rollers 318 and 320. The paper 308 is guided between and clamped by the driving rollers 318 and 320 and fed out by the rotation of the driving rollers 318 and 320 while it is pressed by and brought into contact with the driving rollers 318 and 320. The print mechanism 314 comprises a print head 322 and a platen 324 which are confronted to each other while interposing the paper feed passage 310 therebetween. When the print head 322 is driven, the paper 308 is printed. Printing form is varied depending on the kind of the paper 308. If a heat sensitive paper is used, an ink ribbon is not needed while if an ordinary paper is used, a color medium such as the ink ribbon is needed. A cutter mechanism 316 is composed of an independent unit and contains therein a cutter blade 326 which slides in the direction perpendicular to the feeding direction of the paper 308. The cutter blade 326 is driven by a slide driving mechanism. In the cutter mechanism 316, when the cutter blade 326 slides downward in FIG. 21B, the paper 308 is cut off.
In this printer, the paper 308 is discharged from the port 306 while it is printed. Upon completion of printing, the paper 308 is discharged continuously by a given amount and cut off by the cutter blade 326 when the cutter blade 326 slides.
If such a printer is employed by the issuing apparatus for issuing the receipts or the tickets, it is expected that the recipient stands by for completion of printing while picking up an end of the paper 308 with fingers. It is also expected that the recipient obstructs the discharge of the paper 308. FIG. 22 shows an example of a case where the recipient stands by for an issuance of the paper 308. That is, when the recipient stands by while picking up the paper 308, the paper 308 is prevented from being smoothly fed so that the paper 308 while it is fed on the paper feed passage 310 is liable to generate bending 328. The bending 328 gives unnecessary stress on the paper 308 in the direction opposite to the discharge direction of the paper 308. As a result, the paper 308 is bent inside the printer and a normal discharge operation can not be performed, which causes a paper jam, which eventually leads to malfunction of the apparatus.
FIG. 23A shows a case where the recipient forcibly pulls out the paper 308 to be discharged. If tension T is applied to the paper 308, the tension T applies unnecessary load to an edge of the cutter blade 326 in the direction perpendicular to the sliding direction F. If the load is extremely large, an edge 330 of the cutter blade 326 is damaged as shown in FIG. 23B. If the edge 330 is bent, there occurs a possibility that the cutter blade 326 can not slide or the cutting operation is deteriorated.
In such a conventional printer, there is provided a means to prevent the recipient from touching the paper 308 until printing on the paper 308 having a predetermined length has been finished and the printed paper 308 has been discharged. For example, such a printer is disclosed in Japanese Utility Model Laid-Open Publication No. 5-29765. In this printer, a cover having a depth corresponding to the length of the paper 308 to be issued is attached to a paper discharge portion and the paper 308 is guided within the cover to prevent the recipient from touching the paper 308 and the paper 308 can be discharged from the cover only when the paper 308 is cut off.
However, such a printer has the following problems. Since the cover protrudes from the printer, the cover per se is liable to be damaged. Furthermore, since the size of the cover corresponds to the length of the paper 308, if the length of the paper 308 to be issued is changed, it must be changed to correspond to the changed length of the paper 308, which makes the issuing apparatus large.
There has been proposed paper discharge apparatuses as a means for coping with the aforementioned problems as disclosed in Japanese Patent Laid-Open Publication No. 1-181659 and U.S. Pat. No. 5,125,393. In such apparatuses, the paper is slackened and on standby in the discharge passage until a printing operation is completed, thereby preventing the recipient from receiving the paper but the paper is cut off and discharged from a discharge port upon completion of the printing operation.
However, in case that the recipient blocks the paper discharge port of these paper discharge apparatuses intentionally by fingers, Japanese Patent Laid-Open Publication No. 1-181659 does not disclose any means to cope therewith, which causes a problem of paper jam. In U.S. Pat. No. 5,125,393, if the paper discharge is blocked, the paper which has been on standby within the cover is guided downward by rollers. In this case, namely, if the paper is discharged through another route instead of the discharge port, the recipient can not receive the paper, which causes another problem.
Furthermore, in such a paper discharge apparatus, since a passage extending from the print mechanism to the discharge port is made long and the rollers are used for discharging the paper, conditions of the paper influences upon the feeding of the paper by the rollers. There is a possibility that such an apparatus is installed indoor and outdoor and is used under high temperature and high humidity. Although a standardized paper is used as the paper, there occur such problems that the standardized paper is softened under high temperature and high humidity and the paper is liable to be deformed at the portion where it is held between the contacted rollers due to pressure by the contacted surfaces of the rollers. The softened paper generates excessive friction between the rollers or it is adhered to the surfaces of the rollers, so that the paper is difficult to be fed. If wrinkles are generated on the paper between the surfaces of rollers due to the pressure by the rollers, the paper is liable to be bent at the wrinkled portions, so that the paper is difficult to be clamped by the rollers. In case of a rolled paper, it is liable to be curled or wrinkled, which prevents the paper from being fed between the rollers. This causes the paper jam. Japanese Patent Laid-Open Publication No. 1-181659 employs a driving lever for assisting the paper to inroad between the rollers. However, a mechanism of this driving mechanism is complicated and it rather causes the paper jam.